Expanding on the simple approach above, let the caller know who they've reached. This will not only eliminate people leaving voicemails by mistake, but it will reassure the caller that they have called the number they intended.
Users often don’t invest enough time into their messages, resulting in incomplete, unprofessional, or otherwise under-whelming greetings. Sure, crafting a greeting doesn’t sound all that complicated; however, there are a number of pitfalls users can fall into—i.e. informality, terseness, sincerity, lack of direction, and more. While none of these sound too catastrophic, they are often interrelated. As such, they tend to worsen any problem. For example, humor can cause informality, worsen ambiguity, and weaken sincerity. That being said, users should strive to avoid ALL these pitfalls.

The main point that we want to drive home with this article is that you shouldn’t overthink your business voicemail greeting. Just keep it short, and state the relevant information.
“Hi, thanks for calling the office of (insert your name). I’m away from my desk or out of the office. Please leave your name and number, and I’ll return your call as soon as possible. If you need immediate assistance, please hang up and reach our customer support team at (insert phone number). Thanks, and have a great day!”